Plasma carbonitriding reaction characteristics of Sm2Fe17

Simultaneous introduction of carbon and nitrogen to the crystal lattice of Sm{sub 2}Fe{sub 17} (carbonitriding) took place by glow discharge under differential pumping conditions of mixed gases in the ternary system CH{sub 4}-N{sub 2}-H{sub 2}. The initiation temperature for plasma carbonitriding (ca. 573 K) was lower than those of the thermal processes for Sm{sub 2}Fe{sub 17}N{sub x} and Sm{sub 2}Fe{sub 17}C{sub x} (above 673 K). Plasma reaction at 723 K produced a compound with chemical formula Sm{sub 2}Fe{sub 17}C{sub x}N{sub y} (x + y = {approximately} 3) although no material with such composition was obtained by the thermal reaction under the same temperature and atmosphere conditions. The X-ray photoelectron signals of C1s and N1s demonstrated that the carbon and nitrogen in Sm{sub 2}Fe{sub 17}C{sub x}N{sub y} are of metal carbide and nitride. The Curie temperature ({Tc}) of the resulting Sm{sub 2}Fe{sub 17}C{sub x}N{sub y} sample was above 750 K, and the coercivity value was about 9.07 kA cm{sup {minus}1} after a ball-milling treatment up to a particle size {approx_equal}3 {mu}m. 18 refs., 7 figs., 2 tabs.